For the primary endpoint of RFS in the overall study population, the one-year RFS rate was 75.4 percent (95% CI, 71.3-78.9) for Keytruda compared to 61.0 percent (95% CI, 56.5-65.1) for placebo. For the co-primary endpoint of RFS in patients whose tumors were considered PD-L1 positive, Keytruda demonstrated significantly prolonged RFS compared to placebo.

Keytruda is the first anti-PD-1 therapy to show RFS benefit across stage IIIA (> 1 mm lymph node metastasis), IIIB and IIIC melanoma. The RFS benefit was also seen regardless of BRAF mutation status (HR=0.64 [99% CI, 0.42-0.96] for patients with wild-type BRAF status; HR=0.57 [99% CI, 0.37-0.89] for patients with mutant BRAF status). As previously announced, Merck is working to submit data from EORTC1325/KEYNOTE-054 to regulatory agencies in the U.S. and around the world.

“These data demonstrate compelling evidence that adjuvant treatment with Keytruda provides significant recurrence-free survival benefit after surgery in patients with high-risk Stage III melanoma,” said Roy Baynes, M.D., Ph.D., senior vice president and head of Global Clinical Development, chief medical officer, Merck Research Laboratories. “These are the first data for Keytruda in the adjuvant setting and mark an important advancement for the treatment of resected stage III melanoma. We are pleased to be sharing these data with global regulatory authorities.”

Adjuvant therapy refers to additional cancer treatment given after the primary treatment to lower the risk that the cancer will come back. Adjuvant therapy may include chemotherapy, radiation therapy, hormone therapy, targeted therapy, or biological therapy.